It is commonplace in homes today to have a telephone instrument and a television set located in close proximity to each other. Since there is no interface between the two pieces of equipment the user must control each one separately, and conflicts in the operation of the two pieces of equipment sometimes arise.
More specifically, many television sets of recent manufacture are equipped with a remote control device for controlling ON-OFF, channel selection, volume, and selective muting functions. Such a remote control device typically operates by means of an infrared signal that is transmitted to the TV set, and requires positive actuation by a human operator either to initiate or to terminate the muting of the sound from the television set.
The telephone may be a single instrument located in the same room as the TV set, and when it rings in response to an incoming call there is an immediate conflict between the sound systems of the two appliances. If the person who is watching the television set also answers the telephone call, then he or she would ordinarily want to mute the sound output of the television set. But, if one person in the room is watching the TV while a second person in the same room places an outgoing call on the telephone, the continuing sound from the TV will interfere with the telephone caller, or vice versa, unless the person watching the TV takes necessary action for muting the TV sound.
Quite commonly a residence has several telephone instruments on a single telephone line but located in different rooms. In that situation the nature of the conflict between telephone and television is somewhat different. Specifically, if someone in a room other than where the television set is located wishes to place an outgoing call on the telephone, there would be no necessity for muting the sound of the TV set. But for an incoming call that necessity would still exist.